COMPARISON OF UNIVERSAL FIELD-ORIENTED (UFO) CONTROLLERS IN DIFFERENTREFERENCE FRAMES

The principle of the Universal Field Oriented (UFO) controller, operat ing in an arbitrary reference frame, is applied to a CRPWM inverter, D ue to its high degree of generality the UFO controller is compatible w ith rotor, stator, and airgap flux field oriented control, The authors compare the stability regions and the steady state performance of the se three types of controllers applied to the same machine, The rotor f lux based controller has been selected as the basic reference. Digital simulation results are carried out to show that the performance of th e complete UFO system, i.e., combined direct and indirect UFO, in a no n rotor flux based reference frame leads to a robust high performance drive with no dependency on machine parameters in steady state.